1/x+1/y=a----(1)
1/y+1/z=b----(2)
1/z+1/x=c----(3)
(((1)+(2)+(3))/2)-(1)
(((1)+(2)+(3))/2)-(2)
(((1)+(2)+(3))/2)-(3)
x=(a+c-b)/2;
y=(a+b-c)/2
z=(b+c-a)/2